130 chassis flex - how much?

[PWat]

I'm about to design & build a new frame for my 130 dual-cab's tray. (It will include room for a second fuel tank, draw, side storage, etc.)

I've read in a lot of places about making allowance for the chassis flexing / twisting, including the use of rubber mounts at the front in order to prevent the chassis cracking. (Which has already started to happen.) I already know that if I park on a funny angle it's hard to open some doors!

Does anyone know how much it actually twists? Are we talking a few mm, a cm or so, or more?

[shack]

I'm about to design & build a new frame for my 130 dual-cab's tray. (It will include room for a second fuel tank, draw, side storage, etc.)

I've read in a lot of places about making allowance for the chassis flexing / twisting, including the use of rubber mounts at the front in order to prevent the chassis cracking. (Which has already started to happen.) I already know that if I park on a funny angle it's hard to open some doors!

Does anyone know how much it actually twists? Are we talking a few mm, a cm or so, or more?No idea, there is however an official document that details quite well how to design tray mounts and positioning, it'd be worth chasing up

[POD]

I think you're looking at a few cm across the diagonals of the tray. You could jack up, or ramp, one rear corner and measure spring heights to get a good idea of it.

[PWat]

I think you're looking at a few cm across the diagonals of the tray. You could jack up, or ramp, one rear corner and measure spring heights to get a good idea of it.

I'll thought about jacking up a corner but I don't think the change in diagonal length will be large enough to be measurable. (Using pythagoras, if the diagonal starts at 1m and one corner is twisted up 20mm, the diagonal will change by less than 1mm.)

Perhaps I'll create a super-rigid light box frame and just sit it on the chassis mounts.

[d130 beaut]

Hi don’t really believe its an issue did basically what your planning over 100k ago never had anything go wrong ,many long trips fully loaded including Csr ,gibb ect . I removed tub and fitted an aluminium tray( had enough space under the tray to fit a cheap fuel tk from wreckers ) Fitted locally made canopy bolted straight onto tray . At times i have started trips with 210 ltrs fuel/ 160 water , i did also fit airbags inside heavier coils on rear.

[Tote]

There is a document on body building here https://www.aulro.com/afvb/local_links.php?catid=7 called the Defender cab chassis conversion manual. It will tell you everything you need to know. Basically if you fit a rigid steel tray without provision for flex you will tear off the front body mounts.

There's lots of good ideas in this thread as well 130 DC Trays (https://www.aulro.com/afvb/90-110-130-defender-county/267919-130-dc-trays.html)

Mine now has nearly 120,000 KM on it and no problems although I have been in situations when I have heard the tray unloading from the front mounts when flexing.

Regards,
Tote

[MLD]

to add to Tote's link to the cab chassis tray mount. read the info on pages 10 to 13. the instructions are clear that the tray is hard mounted on the front mounts and rear cross member only. the in-between mounts are for resting support only and not hard attached.

as for flex, i have a pretty stiff welded tube tray. my mounts are wider than the chassis on the front by use of a cross member and same on the rear. i run long travel shocks and can disconnect 550mm free length coils. when crossed up the doors are jammed so there is a bit of flex in the chassis. That is all to say, in almost 10 years & 150,000 kms of this configuration, and lots of crossed up driving, there are no cracks on the chassis mounts. Follow LR's instructions and all will be good.

[PWat]

There is a document on body building here https://www.aulro.com/afvb/local_links.php?catid=7 called the Defender cab chassis conversion manual. It will tell you everything you need to know. Basically if you fit a rigid steel tray without provision for flex you will tear off the front body mounts.

There's lots of good ideas in this thread as well 130 DC Trays (https://www.aulro.com/afvb/90-110-130-defender-county/267919-130-dc-trays.html)

Mine now has nearly 120,000 KM on it and no problems although I have been in situations when I have heard the tray unloading from the front mounts when flexing.

Regards,
Tote

Thanks for the info - I like your spring mounting system.

I had seen that thread before but got distracted with wondering how much Fubar's construction weighed! (As well as why he used RHS in the least-strong orientation.)

[PWat]

to add to Tote's link to the cab chassis tray mount. read the info on pages 10 to 13. the instructions are clear that the tray is hard mounted on the front mounts and rear cross member only. the in-between mounts are for resting support only and not hard attached.

as for flex, i have a pretty stiff welded tube tray. my mounts are wider than the chassis on the front by use of a cross member and same on the rear. i run long travel shocks and can disconnect 550mm free length coils. when crossed up the doors are jammed so there is a bit of flex in the chassis. That is all to say, in almost 10 years & 150,000 kms of this configuration, and lots of crossed up driving, there are no cracks on the chassis mounts. Follow LR's instructions and all will be good.

Thanks - I'd read that document before but missed the bit about not bolting the in-between mounts. It's interesting that it's very clear about rigid mounts at the back but doesn't say what to do at the front. My current tray is rigid bolted in 6 places and doesn't attach to the rear cross-member - as I've already got small cracks in the chassis near the front mounts I think I'll put some rubber in there! (I haven't treated it very kindly - last year we did a 41000km big-lap with a heavy camper on the tray.)